Apple launched the fourth-generation iPad in October, with a few changes from the third-generation. It introduced a new A6X processor, a FaceTime HD camera, and the new Lightning connector. Despite being better than the previous iPads, the new iPad isn’t selling as well as the older generation iPads. And why is that? The iPad mini, dubbed “Mini the Cannibal,” is stealing all the sales from its larger version.

A poll of 50 Apple Stores by Citi this week found limited stock of the iPad mini, but there was plenty of stock available of the iPad 4. Among the stores included, 80 percent said that some version of the mini was on the shelves, while 96 percent said that overall availability was limited based on the amount, storage options, and colors that consumers were buying. The 32GB iPad mini was found to have the greatest availability.

Meanwhile, every store surveyed said the fourth-generation Retina iPad was available, and only 6 percent of the stores said that availability was limited.

Citi analyst Glen Yeung said in a note to investors: “While not explicity asked, it is clear in our survey that [the] iPad 4 is not selling well, cannibalized by Mini sales.”

Yeung estimates that Apple had 10 million iPad minis manufactured for the current quarter, and 10-15 million of all other iPads combined. Obviously Apple expects the iPad mini to be a big hit this holiday season.

Yeung also kept in mind the fact that iPad mini supplies were limited due to manufacturing problems, and noted a report from November 27 that claimed one of Apple’s two display manufacturers, AU Optronics, was having production yield difficulties causing supply constraints. AU Optronics has since denied this, saying iPad panel shipments have remained in target.